Membrane association of sucrose synthase: changes during the graviresponse and possible control by protein phosphorylation.
Sucrose synthase (SuSy) plays an important role in sucrose degradation and occurs both as a soluble and as a membrane-associated enzyme in higher plants. We show that membrane association can vary in vivo in response to gravistimulation, apparently involving SuSy dephosphorylation, and is a reversible process in vitro. Phosphorylation of SuSy has little effect on its activity but decreases its surface hydrophobicity as reported with the fluorescent probe bis-ANS. We postulate that phosphorylation of SuSy (and perhaps other membrane proteins) is involved in the release of the membrane-bound enzyme in part as a result of decreased surface hydrophobicity.
Winter
H
H
U.S. Department of Agriculture, Agricultural Research Service, Raleigh, NC, USA.
Huber
J L
JL
Huber
S C
SC
D000255:Adenosine Triphosphate / Q000378:metabolism; D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D015153:Blotting, Western; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000378:metabolism; D005964:Glucosyltransferases / Q000032:analysis / Q000378:metabolism*; D006112:Gravitation; D008565:Membrane Proteins / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000378:metabolism; D011233:Precipitin Tests; D012995:Solubility; D014532:Uridine Diphosphate Glucose / Q000378:metabolism; D003313:Zea mays / Q000201:enzymology*
D000817:Anilino Naphthalenesulfonates; D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D008565:Membrane Proteins; D010940:Plant Proteins; C035763:5,5'-bis(8-(phenylamino)-1-naphthalenesulfonate); D000255:Adenosine Triphosphate; D005964:Glucosyltransferases; C022699:sucrose synthase; D017868:Cyclic AMP-Dependent Protein Kinases; D014532:Uridine Diphosphate Glucose